pihlfeldt



"- 625J99- Patented May I6, 1899..

O. PIHLFELDT.

CYCLE CHAIN ADJUSTMENT.

[Application filed Apr. 16, 1898.) BL) 2 Sheets-Sheet l.

d WITNESSES INVENTOR 02 JZZ 24 HE "cams ravens no. Moro-Luna. WASHINGYDN, p. c

Patented May [6-, I899.

O. PIHLFELDT.

CYCLE CHAIN ADJUSTMENT.

(Application filed Apr. 16, 1898.)

2 Sheets--Sheet 2.

(No Model WITNESSES -NITED STATES PATENT OFFICE.

OLAF PlI-ILFELDT, or BIRMINGHAM, ENGLAND.

CYCLE-CHAIN ADJUSTMENT.

SPECIFICATION forming part of Letters Patent No. 625,199, dated May 16, 1899. Application filed April 16, 1898. Serial No. 677,898. (No model.)

land, have invented certain new and useful Improvements in Cycle-Chain Adjustments, of which the following is a specification.

This invention relates to cycle-chain adjustments, and has for its object to provide a means for obtaining parallel adjustment of the back wheel by the rotation of the hub spindle only, and which said means is capable of being employed particularly in conjunction with the present pattern of chainadjusting back-fork ends having slot-races in which the hub-spindle moves or is traversed.

Figure 1 of the accompanying drawings represents an elevation, partly in section, of a portion of the rear part of a safety-bicycle fitted with my improved means for adjusting the drive-chain by altering the position of the back-wheel hub-spindle relative to the driving crank-axle, consisting of a pair of involute cams made fast upon and capable of turning with the hub-spindle and adapted where one end of the said spindle is turned to wipe against the end of stationary tracing-pegs carried in the back jaws and arranged to impinge on the peripheries of the said cams. Figs. 2 and 3 represent like outside elevations of one of the slotted chain-stay ends and adjusting means and respectively show the involute cam in two different positions relative to the tracing-peg which determined the position of the spindle within the slot. Thus Fig. 2 shows the parts in their normal or starting positions, and Fig. 3 shows the cam after having made about half its throw and the spindle moved outwardly along the slot to a corresponding extent. Fig. 4 is an inside elevation ofthe fork end and the adj ustmentfittings, with the spindle in section and the several parts in the same positionsas in Fig.

3. Fig. 5 is an inside elevation of the fork end and the stationary tracing peg, thespindle and cam secured thereon not being shown. Fig. 6 is a transverse longitudinal section of Fig. 5 upon the dotted line at, and Fig. 7 is a side elevation of the involute cam. Fig. 8 is an elevation of the wheel-hub with its flatted spindle and disassembled fittings thereof,com prisingthe adj Listing-cams, spindle washers, and lock-nuts, those adjacent to the righthand end being shown in vertical section, while those at the other end are represented by edge views. Fig. 9 is a detail side elevation showing a modification of the invention. Fig. 10 is a horizontal sectional view taken on the line 03 Fig. 9; and Fig. 11 is a vertical sectional view of the cam represented in Figs. 9 and 10.

The same letters of reference indicate corresponding partsin'the drawings.

Fitted upon each end a of the back wheel spindle o; of a bicycle and coming, preferably, on the inner face of the slotted fork-end plate I) of the chain-stay b is an involute cam c of the figure technically known as a snailplate, with the edge or periphery c of same terminating in a shoulder or step 0 corresponding in extent to the throw of the caln and extending from the lowest to the highest point of the volnte. I propose that therniddle on the outer side of each cam should have a boss or short sleeve 0 suitable for a chambered sinking or recess b taking into or formed around the edges of the slot b of the fork-end plate and coming upon the inner side thereof, and that each cam should be made fast to the spindle by the hole 0 therein, having fiat sides 0 taking upon corresponding flats a 011 the end of the spindle. The inner face may be chambered or sunken, as at c, for receiving a reduced or stepped outer end a of the adjacent bearing-cone a of the hub (1 Also located, preferably,on the inner side of each fork-end plate and within the path of the movement of the involute cam is a fixed stop or stationary tracing-peg d, against the opposed end d of which the edge or periphery of the said cam wipes or traces on the turning of the spindle for varying the distance between the driving and driven axles, whose parallelism is maintained by both cams, which have an equal throw, being moved around with the spindle.

The extreme endsof the spindle may have flats or facets for facilitating the rotation of the said spindle and the camsbodily together. These'said ends are also screwed to take nuts or looking expedients f and wash-- ers e, by which the hub-spindle and the cams are clamped to the fork ends after adjustment.

I wish it to be understood that the whole of the periphery of the cam from the lowest to the highest part of the throw is operative or available for use in giving the necessary parallel traverse to the spindle and that the point of impingement of the cam against the fixed stop or tracing-peg is nearly in the same line as the center of the spindle and in the direction of pull of the chain thereon.

Fig. 10 represents an elevation of a modified form of my invention in which the spindle is traversed by means of a pair of plates made fast so as to turn with it and each provided on its outer face with an involute channel or box-cam, into which the end of a stationary stop or tracing-peg takes.

Fig. 11 is a horizontal section of Fig. 10 upon the dotted line m c is the cam-plate, and c is the involute channel cut or formed in the outer face thereof and having an open end 0 to admitof the same being engaged with the stop or stationary tracing-peg cl, whose shank d is made fast to the slotted fork-end plate I) of the chain-stay Z). The cam-plates are made fast to the axle by similar means as described in connection with the first form of my invention. By the tracing-pegs thus being engaged into and confined within the involute channels of the cam-plates the said cams and pegs are constantly in operative connection with one another, so that the rotation of the spindle in the one direction'will cause it to traverse outward within the fork-end slots for pulling up or tightening the chain, While when the spindle is turned in the reverse direction it is drawn inward and the chain is slackened to a corresponding extent.

The application of my invention to cycles (including tricycles) other than those having the ordinary slotted fork-end plates or back jaws differs in no essential respect from its application to the arrangements herein described.

Having fully described my invention, what I desire to claim and secure by Letters Patent is 1. The combination with the rotatable rearwheel axle of a cycle and the slotted end plates in which said axle turns and is movable back and forth, of stops secured on said slotted end plates substantially in line with said axle and in the direction of pull of the chain, and two plates having involute camengaging portions, secured to the axle and adapted to turn in unison therewith, and having their engaging portions bearing against said stops, as and for the purpose set forth.

2. The combination with the rotatable rearwheel axle of a cycle and the slotted end plates in' which the end portions of the axle turn and are movable back and forth, of stops secured to said slotted end plates, substantially in line with said axle and in the direction of pull of the chain, and plates secured to the axle to turn in unison therewith, and

provided with in volute cam-grooves in which said stops fit, as and for the purpose set forth. 

